Vukac Hranić Kosača (Serbian Cyrillic: Вукац Хранић Косача; fl.
Both Vukac and Vuk were subordinate to their powerful older brother Sandalj, who governed Hum (Humska zemlja), southernmost part of the Kingdom of Bosnia.
[1] Sandalj had succeeded their uncle Vlatko Vuković as Grand Duke of Bosnia and Lord of Hum in 1392.
Vukac held part of his family's hereditary lands in Podrinje (mentioned in 1415), and the region of Govza by the Bistrica river, and the town of Jeleč, which he was given following the death of his younger brother Vuk in 1425.
[1] Stjepan was since 1419 mentioned in documents alongside his father and uncles as he had already back then been chosen to succeed Sandalj in the future.